Rotary joints are utilized to establish communication between a fixed conduit system and rotating member, such as a heating or cooling drum. The joint includes a housing having a chamber defined therein having a port for communicating with a fixed conduit system, and a rotary member, such as a sleeve or nipple, is located withing the housing and supported thereon by bearings. Sealing means establish fluid tight seals between the housing and the rotatable sleeve, and the sleeve is coaxially aligned with the rotating member being serviced. With rotary joints, the life and efficiency is related to the ability of the seal to remain efficient and operative, and a wide variety of sealing arrangements have been employed with rotary joints.
While rotary joints utilize both friction and anti-friction bearings, it is highly desirable in many applications to employ anti-friction bearings, and in such joints it is the practice to use a pair of ball bearings mounted upon a tubular sleeve axially spaced relative to each other in order to assure concentricity of the sleeve to the bearing and housing during operation. The use of a pair of ball bearings is expensive, but it is the common practice to use the bearings in pairs in order to achieve axial rigidity and prevent misalignment which would adversely affect the sealing as provided by known rotary joint seal assemblies.
From a cost standpoint, it is preferable to use only a single anti-friction bearing in a rotary joint. However, difficulties encountered with respect to maintaining alignment between the rotary and stationary components with attendant problems of maintaining seal integrity render single anti-friction bearing joints usable in only relatively few applications, and floating seals are sometimes used which have self-aligning capabilities.
It is an object of the invention to provide a rotary joint utilizing a single anti-friction bearing between static and dynamic components, and wherein self-aligning sealing apparatus is employed which is of an economical construction, and may be readily installed.
An additional object of the invention is to provide a rotary joint employing a single anti-friction bearing wherein a floating and self-compensating seal assembly is used which automatically accommodates itself to misalignment with respect to the axis of joint rotation, and wherein wear is automatically compensated for by means of biasing structure.
Yet an additional object of the invention is to provide a rotary joint utilizing a single anti-friction bearing wherein the bearing supports a rotating sleeve received within the bearing inner race, and an adapter removably affixed to the sleeve laterally engages the inner bearing race locating and positively retaining the sleeve within the inner bearing race.
Additionally, an object of the invention pertains to rotary joint structure wherein an economical joint may be produced having a relatively wide range of self-alignment, and wherein a variety of conduit attaching adapters associated with an inner sleeve may be selectively mounted upon the sleeve, and wherein the adapter aids in maintaining the sleeve in operative relationship with anti-friction bearing means.
In the practice of the invention a housing includes a chamber defined therein communicating with at least one port associated with a fluid supply or discharge conduit. A single anti-friction ball bearing is mounted within the housing chamber and a tubular sleeve is located within the bearing inner race and positively associated therewith by a threaded adapter mounted upon the sleeve and engaging a lateral side of the inner bearing race.
A seal assembly is interposed between the sleeve and the housing having a sealing surface which lies in a plane substantially perpendicular to the sleeve axis of rotation, and the sealing assembly includes an annular sealing surface against which an annular seal ring is biased by a compression spring. The seal ring is maintained in place by a resilient elastomer support ring slidably supported within the housing, and this resilient support ring permits the seal ring to compensate for deviation of the sealing surface from the true axis of rotation, the elastomer permitting the seal ring to maintain a sealing relationship with the sealing surface defined on the sleeve, and the spring insuring an effective seal between the seal ring and sealing surface regardless of whether the rotation of the sleeve is true.
A radially extending shoulder is defined upon the sleeve adapted to engage a lateral edge of the inner bearing ring, and a conduit adapter threaded upon the sleeve engages the opposite bearing inner race lateral edge whereby threading the adapter upon the sleeve positively locks and positions the sleeve relative to the bearing inner race. The adapter may take any desired form, such as male threaded, female threaded, or the like, and the entire rotary joint apparatus is of an economical construction which may be readily manufactured by high production techniques.